The microwave dielectric properties of ceramic/bismuth zinc borosilicate (BZBS) glass composites were investigated. The crystalline phases of ZnAl2O4 with a spinel structure in the Al2O3/BZBS glass composite and Bi2Ti2O7 with a cubic pyrochlore structure in the TiO2/BZBS glass composite were observed, indicating that BZBS glass was a reactive glass in these systems. A one-stage sintering occurred in the Al2O3/BZBS glass composite whereas a two-stage one might occur in the TiO2/BZBS glass composite. The dielectric constant (epsilon(r)) of the Al2O3/BZBS glass composite exhibited almost the same value of about 10 within the sintering temperature range between 600-950 degrees C, implying that the application of the Al2O3/BZBS glass composite to substrates may therefore be shown to be appropriate. For the TiO2/BZBS glass composite, however, in improvement of the temperature coefficient of the resonant frequency (tau(f) = +119 ppm/K) is necessary for the application as LTCC materials although the dielectric constant of this system had I proper value (similar to 56) for in application to filters.
Keywords: LTCC; Ceramic/gass; Al2O3; TiO2; Bismuth-zinc borosilicate glass